This project takes an international consortium approach using single cell transcriptomics, human cellular physiology and anatomy, and neuronal modeling to begin to create an atlas of human brain cell types as a community data resource. The project is structured around two main components to study different cellular properties in human tissues. The first approach uses transcriptomics to survey cell types across the brain, and to study detailed cellular diversity in several structures relevant for neuropsychiatric disease including the hippocampus and dorsolateral prefrontal cortex. The second approach aims to characterize the anatomical and physiological properties of transcriptionally-defined cortical neurons in living human tissues derived from neurosurgical resections to treat epilepsy or brain tumors. The project aims to standardize methods for human Patch-seq using patch clamp slice electrophysiology to study the structure, function and molecular properties of cortical cell types. Finally, tools will be developed to classify cell types, perform neuronal modeling to understand and predict the function of cell types, and compare cell type properties between mouse and human. All of these data will be mapped to a 3D human common coordinate framework. The outcome will be the first detailed study of human brain cell types and the development of standardized methods for human brain study.